A thin film technology has been widely utilized for the purpose of the reduction in device sizes and the increase in device performances. There are various film formation methods used for the manufacture of the thin film. Examples are a deposition method, sputtering, ion plating, CVD, and laser ablation. These methods are used depending on the purpose. The deposition method comparatively excels in productivity. In the deposition method, resistance heating, induction heating, electron beam heating, or the like is used as a method of applying energy for heating and evaporating a film formation material.
One problem of the deposition method is the use efficiency of the film formation material. To be specific, from the standpoint of manufacturing cost, it is important to efficiently precipitate and deposit the evaporated, scattering film formation material on a substrate. To solve this problem, it is effective to use a nozzle-type evaporation source. In the case of using the nozzle-type evaporation source, the film formation material can be emitted from only an opening surface of a nozzle. Therefore, the scattering of the film formation material can be limited. By locating the opening surface and the substrate close to each other, the film formation material can further efficiently adhere to the substrate.
PTL 1 discloses that: in a device configured to form a synthetic resin coating film, open-close devices and evacuating devices are respectively provided for two raw material monomer evaporation source nozzles, and each of inner portions of evaporation source containers is maintained at a constant degree of vacuum regardless of the open or close state of the open-close devices. PTL 1 describes that with the above configuration, the synthetic resin coating films of the same quality are reproducibly, stably formed on the substrates.
PTL 2 discloses that in a method of manufacturing a negative electrode for a nonaqueous electrolyte secondary battery, lithium is supplied by a dry film formation method to a plurality of columnar bodies projecting from the surface of a current collector.
In the deposition method, the film formation material is heated to be adjusted such that the film formation material has, in vacuum, vapor pressure necessary for the film formation. With this, the film formation material is evaporated, and the film formation is performed. After predetermined film formation is completed, the film formation material may be cooled, and the pressure in a vacuum chamber is then returned to normal pressure. However, if the film formation material evaporates and scatters in the process of cooling the film formation material, material loss occurs. Therefore, it is important to prevent this loss from the standpoint of manufacturing cost.
PTL 3 discloses a method of performing deposition using an organic thin film material. According to PTL 3, in a state where the organic thin film material is accommodated in an evaporation source container, a vacuum pump is activated to evacuate the evaporation source container, and the organic thin film material is increased in temperature to generate the vapor of the organic thin film material. Then, an evaporation source shutter and substrate shutter provided above an emission opening of the evaporation source container are sequentially opened, and the formation of an organic thin film on the surface of a film formation target object provided in a vacuum chamber is started. When a predetermined film thickness is obtained, the substrate shutter and the evaporation source shutter are closed, and the heating of the thin film material is stopped. Thus, the deposition is terminated. Next, the thin film material is cooled in a state where an inert gas is supplied to the vacuum chamber to suppress the generation of the vapor. According to the method described in PTL 3, since the generation of the vapor of the organic thin film material is suppressed under an inert gas atmosphere, the organic thin film material can be effectively utilized. PTL 3 describes that since the inert gas serves as a heat medium, the cooling rate of the thin film material increases after the film formation.